The aim of the article focused on the theoretical problem of word’s morphological structure. According to the analysis the nature and characteristics of parts of speech in Turkic languages which are considered to be agglitinate are quite different than in flexic lamguages. The research also describes the principles, peculiarities, conceptual contradictions of word’s division into parts of speech. It also enlights the relationships between morphemes, because they build word formation system in Turkic languages